Hey Dogstar,
At this point in time the online store only uses Mastercard and Visa, other payment methods are being investigated for future versions of the online store. In the meantime, I know a lot of other people in the same situation as you and they find ordering online a difficulty. You might want to talk to your bank or look online for a something called a prepaid credit card, they are becoming more and more popular with online shoppers.
Hope this helps!